I am trying to plan a short trip from Venice through Switzerland and back to Milan with my parents who are both quite elderly. So the emphasis is on scenic beauty rather than hiking or skiing etc.This is what I have figured out until now:

7 September: Venice to Verona and then Verona to Innsbruck: 3.5 hours. Possibly go to Garmisch and back or just stay in Innsbruck.

8 September: Innsbruck to Bludenz/Buchs/Bregenz via Arlberg pass for the scenictrain-ride: which is the best end-point ? From here, I think I would like toget to Lucerne (do I have to touch Zurich ? Is there a smart route ?)

9 September - 11 September (Swiss alps, make it to Milan by 11 night): Here I have many options, and this is where I really need advice. I have tried to break it up into 3 options, but perhaps even these are not the most sensible routes...

Option A) Engelberg-Mt. Titlis and Then Locarno-Lugano-Como-Milan or Locarno-Domodossloa-Milan ? Is this a different route than the fast train via the Gothard Pass ? More scenic ?

Option B)Lucerne to Zermatt and then Glacier express to St. Moritz on 10th and return to Milan on 11th via Bernina Express route ?

Option C)Interlaken-Jungfraujoch and then make it to Milan ? Possibly touch Zermatt as well ?

Thanks for the quick reply, Slowpoke !! Yes, I realize that it feels like a crowded trip, but I think my parents would like to see as much as they can during those 3 days, and 6 hour train journeys are a breeze for those coming from India, especially when they are in luxurious and punctual European trains :) OK, perhaps I should not generalize like that: it is just that we quite like being on trains...

I guess I should clarify that when I wrote "Locarno-Lugano-Como-Milan or Locarno-Domodossloa-Milan", I meant a train passing through those locations, and not that we would stop at any of those places.

Also, for Option B, the plan was 9th - Lucern to Zermatt, 10th - Zermatt to St. Moritz (or nearby) and 11th - St. Moritz to Milan (a 5.5 hour journey according to bahn.de: OK, this is not via Tirano, that would probably make the journey impossible)...

Well, you don't have to go through Zurich, but if you will out Innsbruck to Lucerne in the timetable Slowpoke mentioned, you will probably find that it is the easiest route: quick and only one change.

As for your options A to C:

A) You can even include the boat: the Wilhelm Tell Express route. Once you've reached Bellinzona you have two options: proceed to Lugano and onwards to Milan, or the other (longer) route you already found through Locarno and Domodossola (very nice scenery).

B) If you truly love train rides this is a wonderful route. Please see: